Heat exchanger fin



FIG. 1 is a perspective view of our new design for a heat exchanger fin installed with an array of heat exchanger fins in a heat exchanger for a tankless water heater;

FIG. 2 is a top front perspective view of our new design for a heat exchanger fin;

FIG. 3 is a bottom back perspective view thereof;

FIG. 4 is a left elevation view thereof;

FIG. 5 is a right elevation view thereof;

FIG. 6 is a front elevation view thereof;

FIG. 7 is a back elevation view thereof;

FIG. 8 is a top plan view thereof; and,

FIG. 9 is a bottom view thereof.

The broken lines shown in the figures illustrate the environment in which the heat exchange fin is installed and form no part of the claimed design. 

CLAIM The ornamental design for a heat exchanger fin, as shown and described. 